Overview

Tachycardia heartbeat

Tachycardia heartbeat

In tachycardia, an abnormal electrical impulse originating in the upper or lower chambers of the heart interferes, causing the heart to beat faster.

Tachycardia is a common type of heart rhythm disorder (arrhythmia) in which the heart beats faster than normal while at rest.

It's normal for your heart rate to rise during exercise or as a physiological response to stress, trauma or illness (sinus tachycardia). But in tachycardia (tak-ih-KAHR-dee-uh), the heart beats faster than normal in the upper or lower chambers of the heart or both while at rest.

Your heart rate is controlled by electrical signals sent across heart tissues. Tachycardia occurs when an abnormality in the heart produces rapid electrical signals that quicken the heart rate, which is normally about 60 to 100 beats a minute at rest.

In some cases, tachycardia may cause no symptoms or complications. But if left untreated, tachycardia can disrupt normal heart function and lead to serious complications, including:

Heart failure

Stroke

Sudden cardiac arrest or death

Treatments, such as drugs, medical procedures or surgery, may help control a rapid heartbeat or manage other conditions contributing to tachycardia.

Types of tachycardia

Chambers and valves of the heart

Chambers and valves of the heart

A normal heart has two upper and two lower chambers. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood out of your heart. The heart valves, which keep blood flowing in the right direction, are gates at the chamber openings.

There are many different types of abnormal tachycardia. They're classified according to the origin and cause of the abnormally fast heartbeat. Common types of tachycardia include:

Atrial fibrillation. Atrial fibrillation is a rapid heart rate caused by chaotic, irregular electrical impulses in the upper chambers of the heart (atria). These signals result in rapid, uncoordinated, weak contractions of the atria.

Atrial fibrillation may be temporary, but some episodes won't end unless treated.

Atrial fibrillation is the most common type of tachycardia. Most people with atrial fibrillation have some structural abnormalities of the heart related to underlying conditions such as heart disease or high blood pressure. Other factors that may contribute to atrial fibrillation include a heart valve disorder, hyperthyroidism or heavy alcohol use.

Atrial flutter. In atrial flutter, the heart's atria beat very fast but at a regular rate. The fast rate results in weak contractions of the atria.

Atrial flutter is caused by irregular circuitry within the atria. Episodes of atrial flutter may resolve themselves or may require treatment.

People who experience atrial flutter also often experience atrial fibrillation at other times.

Supraventricular tachycardia (SVT). Supraventricular tachycardia is an abnormally fast heartbeat that originates somewhere above the ventricles. It's caused by abnormal circuitry in the heart that is usually present at birth and creates a loop of overlapping signals.

Ventricular tachycardia. Ventricular tachycardia is a rapid heart rate that originates with abnormal electrical signals in the lower chambers of the heart (ventricles). The rapid heart rate doesn't allow the ventricles to fill and contract efficiently to pump enough blood to the body.

Ventricular tachycardia episodes may be brief and last only a couple of seconds without causing harm. But episodes lasting more than a few seconds can become a life-threatening medical emergency.

Ventricular fibrillation. Ventricular fibrillation occurs when rapid, chaotic electrical impulses cause the ventricles to quiver ineffectively instead of pumping necessary blood to the body. This can be fatal if the heart isn't restored to a normal rhythm within minutes with an electric shock to the heart (defibrillation).

Ventricular fibrillation may occur during or after a heart attack. Most people who experience ventricular fibrillation have an underlying heart disease or have experienced serious trauma, such as being struck by lightning.

Mayo Clinic electrophysiologist Fred Kusumoto, M.D., explains what happens in the heart to create atrial fibrillation and what can be done to fix it.

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